Publications
Available to Download:

Galaxies & Cosmology (1974-1987): Early in my career I studied clusters of galaxies, galaxy morphology, and did galaxy redshift surveys. While working primarily with collaborator Stephen A.
Gregory (U. New Mexico, Prof. Emeritus), I completed a series of deep wide-angle redshift surveys to study the
galaxy distribution in and around the richest galaxy clusters in the nearby universe. When mapping the complete 3D galaxy distribution in the vicinity of our initial targets--the Coma cluster and A1367--Gregory and I
recognized for the first time large voids in the galaxy distribution
(
(Gregory and Thompson 1978. ApJ vol. 222, p. 784). In this 1978 paper we used the term "voids" for the first time in the astronomical literature and posed a challenge to theoretical cosmologists to explain this
completely unanticipated structure. For more details on exactly how the discovery
was made, I provide two paths. The first is to download the relatively recent (ca. 2011) manuscript shown at the very top of this page. The second path is to go to the explanation in : Voids
and Superclusters. The latter is a detailed description that was written ~10 years ago. Each successive redshift survey that has been published since 1978 -- CfA, Las Campanas, 2dF, SDSS -- has served to
reconfirm the significance of the beautiful & intricate filamentary structure traced by the
large scale distribution of galaxies.

Instrumentation (1982-1990): In the early 1980's I began to work on projects aimed
at improving the image quality at ground-based telescopes. My first instrument was a microprocessor controlled
tip-tilt system called ISIS which was built while I was working at the Institute for
Astronomy and was used at
Mauna Kea Observatory (Thompson and Ryerson 1983, Proc. SPIE, vol.445, p. 560). Following Foy & Labeyrie's
suggestion that laser guide stars might provide the reference source for Adaptive Optics (AO) systems,
I initiated the first effort to project a sodium laser guide star into the mesosphere above Mauna Kea
Observatory (Thompson and
Gardner 1987, Nature, vol. 328, pg. 229). This was followed by 3 years of intense work with Chester
Gardner and his students in the Univ. of Illinois Electrical and Computer Engineering Dept. to define
many of the pioneering aspects of laser
guided AO systems. Unknown to us, a parallel laser guided AO development effort was underway
by the U.S. Air Force. How our work helped to trigger the declassification of this
Top Secret research is described in the section AO History. In the last 15 years
adaptive optics technology has been integrated into every state-of-the-art large ground-based
telescope, and it is one of the foundation-technologies of the next generation of giant telescopes. Those of us who pioneered this technology know what a struggle it was to convince conventional astronomers to incorporate AO technology into even a single large telescope.

Adaptive Optics Work (1990 - 2009): In 1990 I obtained funds from the
National Science Foundation to begin experiments with Rayleigh scattered UV laser guide stars. These experiments
with a 35 Watt Excimer laser led directly into my Mt. Wilson laser guided AO system called
UnISIS. Unlike AO systems on
giant telescopes, UnISIS has an open and
flexible design. It is laid out on a large optical bench at the Coude focus of the Mt. Wilson 2.5-m telescope.
UnISIS has both laser guide star and natural
guide star AO capabilities. Two science cameras allow images to be taken simultaneously at visual and at near-IR
wavelengths. On the right is an image of a star taken with UnISIS at 2.12 microns (Ks-band) with a Strehl ratio of 0.67. Following the publication of the 2009 summary paper describing UnISIS (Thompson et al. 2009, Pub. ASP, 121, 498-511), I began to work on other projects. This furlough from AO will end whenever I have the opportunity to relocate to Southern California.

Nebular Spectrograph Work (2009 - present): Any astronomical source with a large angular extent and a uniform surface brightness can be detected spectroscopically equally well with a large or a small aperture telescope. The large aperture telescope will provide results with a higher spatial resolution than the small aperture telescope, but both will produce spectra at the same "speed". Although this fact was recognized as early as 1910 by Vesto Slipher, and was eloquently described by Edwin Hubble in his book "The Realm of the Nebulae" (Hubble's tribute to Slipher is in Ch. V), nebular spectrographs generally have not been exploited in modern times. I have recently built a fast fiber-fed nebular spectrograph and have begun to use it at Mt. Laguna Observatory, the only major observatory in California that is not compromised by light pollution. I have placed 14 optical fibers (in a so-called "Integral Field Unit") at the focal plane of a 0.25-m telescope to feed light into the spectrograph. The first results of this research are briefly described here:
Nebular Spectrograph.